The Trump administration asked the Supreme Court on Friday to issue an unusually quick ruling on the Pentagon's policy of restricting military service by transgender people. It's the fourth time in recent months the administration has sought to bypass lower courts that have blocked some of its more controversial proposals and push the high court, with a conservative majority, to weigh in quickly on a divisive issue.

Earlier this month, the administration asked the high court to fast-track cases on the president's decision to end the Deferred Action for Childhood Arrivals program, which shields young immigrants from deportation. Administration officials also recently asked the high court to intervene to stop a trial in a climate change lawsuit and in a lawsuit over the administration's decision to add a question on citizenship to the 2020 census.

The 9th U.S. Circuit Court of Appeals, a frequent target of criticism by President Donald Trump, is involved in three of the cases. Trump's recent salvo against the "Obama judge" who ruled against his asylum policy — not one of the issues currently before the Supreme Court — prompted Chief Justice John Roberts to fire back at the president for the first time for feeding perceptions of a biased judiciary.

Joshua Matz, publisher of the liberal Take Care blog, said the timing of the administration's effort to get the Supreme Court involved in the issues at an early stage could hardly be worse for Roberts and other justices who have sought to dispel perceptions that the court is merely a political institution, especially since the confirmation of Justice Brett Kavanaugh. At an especially sensitive moment for the Supreme Court, the Trump administration is "forcing it into a minefield that many justices would almost surely prefer to avoid," Matz said.

The Supreme Court almost always waits to get involved in a case until both a trial and appeals court have ruled in it. Often, the justices wait until courts in different areas of the country have weighed in and come to different conclusions about the same legal question.

So it's rare for the justices to intervene early as the Trump administration has been pressing them to do. One famous past example is when the Nixon administration went to court to try to prohibit the publication of the Pentagon Papers, the secret history of U.S. involvement in the Vietnam War.